During the assembly phase in the production of vehicles, assembly work is carried out between different pieces, the connection being habitual by means of nut and screw between the piece to connect and the bodywork of the vehicle, such is the case with the sides of the doors, under-parts of the vehicle and other components.
In the case of simple pieces the solution for connection does not present any problem, since the operative can hold the piece with one hand at the same time as he uses the other hand to hold the screwdriver with which he introduces the nut on the screw which projects from the bodywork. However when it is a matter of securing large-sized pieces to the bodywork, as occurs with the under-parts of the vehicle which can be between 1 and 1.5 meters in length, the operative encounters serious problems to support the piece on high at the same time as he screws the nuts to the bodywork of the vehicle which is approaching on an assembly line raised above the floor, normally the assistance of another operative being required to perform this operation.
With the object of resolving the problem described, some means are known for provisional fastening of pieces to the fasteners which emerge from the bodywork, such as those disclosed in the Patent of Invention EP 1 273 811.
These fastening means consist of a first tubular element of plastic material which has an axial internal hole drilled of hexagonal section and from the base of which some arched portions of resilient material project which are deformed and break when the first tubular element is pressed onto the fastener, so that the portions are left inside the first tubular element and constitute the walls in which a thread will be formed during its tightening on the fastener. The fastening means also comprises a second tubular element, mounted after the portions, which consists of a circular base provided with some tabs which project above intended to be coupled to the first tubular element, after the breaking of the portions, and subsequent displacement of the first tubular element toward the second tubular element.
The so-called arched portions between which an internal drilled hole is defined fulfil the mission, in a first instance, of being coupled to the fastener to establish thereby a provisional fastening of the piece to the bodywork. Subsequently after applying pressure on the first tubular element and causing the breaking of the portions, said tubular element descends until engaging on the tabs of the second tubular element. Thereafter the first and the second tubular element tighten jointly on the fastener.
By means of this fastening system, a good tightness is not achieved on the fastener, since it can unscrew/loosen as a consequence of vibration.
Moreover the functional complications of this fastening means are associated with the fact that the breaking of the portions is not obtained at the appropriate place, at the point of separation between the portions and the first tubular element, as well as with the fact that a robust and stable joint/connection is not established between the first tubular element and the second tubular element when one piece engages on the other.
The possibility of developing a nut for fastening of simple and effective construction for the purpose of achieving the quick fastening thereof to the fastener of a support, such as a bodywork, is made feasible by the invention which is disclosed below.